1. Field of the Present Invention
The present invention relates generally to self-contained breathing apparatuses, and, in particular, to means for quickly and reliably connecting a cylinder valve to a pressure reducer in such an apparatus.
2. Background
Self-contained breathing apparatuses (“SCBA's”) are commonly worn by individuals when carrying out activities in hazardous environments, such as when fighting fires and in other smoke- or gas-filled environments, in order to provide the wearer with breathable air. Conventional SCBA's generally include a facepiece, one or more pressurized cylinder or tank, and a hose. The facepiece, which covers the wearer's nose, mouth and eyes and includes a lens for external viewing, is supplied with air from the tanks via the hose. The tanks are secured to the wearer's body by a harness.
Each tank has a rated capacity that is typically a standard value, such as 2216 p.s.i.g or 4500 p.s.i.g., meaning that the pressure in the tank, when full, is approximately the rated capacity. A cylinder valve is attached to each tank to permit pressurized air to be released from the tank when desired. An outlet of the cylinder valve is connected to a first stage pressure reducer which typically reduces the pressure of the air from the then-current pressure (which will be the same or lower than the rated capacity) to a lower level, such as 100 p.s.i.g., and from there through the hose to a second stage pressure reducer, often referred to as a breathing regulator, where the pressure is further reduced to a breathable level. However, some designs utilize only a single pressure reducer for reducing the pressure all the way from the high pressure level of the tank to a breathable level.
Tanks are typically stored fully loaded, or charged, with a cylinder valve in place. However, the rest of the components of the SCBA, including the first stage pressure reducer, normally reside on a user's backframe. When the user needs a new tank, he selects one from storage and installs it on his backframe. The cylinder valve is then connected to the first stage pressure reducer by threading a female CGA fitting, which may be located at the end of a hose that is connected to the first stage pressure reducer, or may be mounted on the first stage pressure reducer itself, to a corresponding male CGA fitting of conventional design, such as a CGA 346 or CGA 347 fitting, on the cylinder valve. Such a fitting is present on virtually all cylinder valves because of various safety standards promulgated by NIOSH, NFPA and the like. Once fully threaded, this connection provides an airtight seal that permits fluid communication between the cylinder valve, and thus the tank, and the first stage pressure reducer.
Unfortunately, the fittings typically include a large number of tightly-spaced threads that require a considerable amount of time and effort to rotate fully into place. This has several drawbacks. First, the process of changing a tank becomes time-consuming, even under the best of circumstances. In the emergency situations that the wearers typically operate in, however, this extra time may be critical to saving life or property. Even worse, if a wearer runs out of air while in a hazardous environment, his safe return may depend on being able to connect to another SCBA wearer's tank, or to a spare tank brought by a rescuer. Not only does the amount of time required to change tanks become particularly critical in such a situation, but such an operation often must take place in heavy smoke or other conditions in which the relatively simple process of threading two fittings together becomes quite difficult. For all of these reasons, a quicker, easier connection means for connecting the cylinder valve of a pressure vessel to the pressure reducer of an SCBA is needed.
Of course, if a different type of fitting or connection means is used to provide the connection between the cylinder valve and the pressure reducer, then it may be useful to provide an additional connection point and fluid access to the interior of the cylinder valve and from there to the pressure vessel, the quick connect fitting, or both. Such a fitting and path could be used to connect an auxiliary air tank to the user's pressure vessel, or to reload the user's regular pressure vessel, without having to disconnect the vessel and cylinder valve from the pressure reducer or remove the SCBA or pressure vessel from his back. Such a connection could bypass the handwheel-controlled valve of the quick connect fitting, making it easier to create air flow into the cylinder valve. In addition, the existence of fittings of two different types provides extra flexibility in connecting the cylinder valve, and further maintains a conventional connection point even if a quick connect fitting is provided. Unfortunately, because known pressure vessels have not heretofore faced such issues, no known pressure vessels provide such an auxiliary fitting.
Another significant consideration when connecting a loaded pressure vessel to a pressure reducer is the pressure present in the vessel. It is important to ensure that a vessel of the proper capacity is connected to the pressure reducer. Conventional pressure reducers are equipped to handle only a single pressure capacity, or have additional functionality that becomes inoperative or improperly operated when used with a pressure vessel of the wrong capacity. In some cases, a higher-than-expected pressure may cause damage to the pressure reducer, while a lower-than-expected pressure may fool the user into thinking that he has more air left than he does. For these reasons and others, a need exists for either a mechanism that prevents a cylinder valve connected to a pressure vessel of a given capacity from being connected to a pressure reducer unless the capacity of the pressure vessel matches the pressure reducer, or a mechanism for permitting a pressure reducer to operate properly with pressure vessels of differing capacities.
Modern SCBA's are increasingly making use of electronics to carry out additional functionality. An example of such an electronics system is disclosed in the commonly-assigned U.S. patent application Ser. No. 10/744,901, entitled “PERSONAL MULTIMEDIA COMMUNICATION SYSTEM AND NETWORK FOR EMERGENCY SERVICES PERSONNEL,” the entirety of which is incorporated herein by reference. Unfortunately, existing cylinder valve/pressure reducer connections are unable to communicate with any such electronics system because they include no mechanical/electrical interface for signaling a successful connection to the electronics system. Similarly, even if a pressure reducer capable of handling pressure vessels of more than one different capacity were available, there is no known means of signaling the electronics system as to which type of pressure vessel were connected to the pressure reducer. Of course, on an even simpler level, it may be important to signal the wearer or another user directly as to whether a successful connection has been made between the cylinder valve and the pressure reducer, particularly if a quick connect mechanism such as the one described herein is used. Thus, a further need exists for a simple interface for signaling an SCBA electronics system as to whether a successful connection has been made or as to the capacity of the tank that has been connected to the pressure reducer, or for triggering an audible or visible alarm based on whether a successful connection has been made.
In general, then, a need exists for a quick connect pressure reduction assembly and cylinder valve that may be utilized more quickly and more easily than existing designs and that provides additional functionality over that available with such designs.